This is a really interesting case, thanks for bringing it up! I hope there’s some active member of that community here who can give an account of what it is like to be in that community.
As someone who didn’t know about this community until about 30 minutes ago, I can only come up with a spontaneous hypothesis:
Consider two general effects of community growth:
- The bigger the community, the more trolls and more trolls discourage active participation because people don’t want to be subject to a “troll attack”.
- The bigger the community, the more diverse the topics discussed.
Consider that the TwoXChromosomes community is about women’s issues and presumably the majority of members are women.
My first hypothesis would then be that communities with a predominantly female membership either attract less trolls or they handle trolls in a better way so that the community does not suffer the negative effects of trolling as much as male communities.
But although that would explain why TwoXChromosomes did better than other forums, it cannot explain why it actually decreased inequality as it grew.
So here’s my second hypothesis: The increased diversity of topics in a growing community can have at least two kinds of effects: (i) the community basically becomes a set of multiple smaller sub-communities which discusses its respective topics in an expert-way, thus discouraging participation of non-experts, i.e. the majority of the members. (ii) the community does not form exclusionary sub-communities but remains open so that the increased diversity of topics actually encourages participation because chances increase that any member finds a topic close enough to their heart to actively contribute.
The TwoXChromosomes community followed the second path because its core identity is that of being a woman (or having access to the experience of being a woman) which makes it difficult to exclude people based on them not being enough of an expert (in being a woman). So as the community grew, more and more lurking members discovered something that related to their own experience and started contributing.